Forever Guard Liner Top Chimney Cap. Fits all factory build double and triple wall chimney systems. This chimney cap will also fit, single wall stove pipe, masonry round clay flue pipe and flexible chimney lining systems. Designed to slip inside the flue pipe, secures with a pressure fit. 24 Gauge 5 in. animal proof 3/4 in. oval hole mesh, that prevents creosote buildup. Fits over the outside of the chimney pipe that has a maximum outside Dia of 13 in. or less and inside chimney pipe Dia of 5 in. Removable hood and screening for easy cleaning. Inside lip prevent water from rolling back into the flue. Copper, 5/8 in. mesh screening and customs sizes are also available. Material: Stainless Steel.